I Promise
by FairyAlchemist400
Summary: Natsu is keeping a secret and it's causing him stress. Unfortunately, Gray just happens to set him off.


_**So, this one-shot is, pretty loosely, based off of a story idea that I have, but I'm not sure if it's going to go anywhere. Therefore, I ended up writing this just so that I could stop thinking about it and focus on my other stories. I don't know if I'll ever actually write the full story, in the future, but it might happen. Who knows?**_

 ** _I'll let you read this as is it, but if you get confused, since this one-shot barely explains any back story, feel free to ask. However, I will tell you that this one-shot takes place before they go to get Makarov, from Alvarez._**

* * *

Natsu sat in the guild hall, with his friends. He was devouring a slab of meat, as he listened to their chatter.

"So, Gray," Lucy asked, conversationally. "what's your goal, for the future?"

"To kill E.N.D.." Gray replied, his eyes hardening.

Natsu felt his stomach drop. This wasn't the first time he heard it, but it always made him sick, anyways.

Lucy sighed. "You know that I wish you the best of luck on that, but I was really hoping for a more...I don't know, normal answer?"

"What's that supposed to mean?" Gray asked, dryly. "A goal is a goal."

Lucy sighed again.

Natsu had stopped eating, as he was queasy. He knew that Lucy didn't mean that she wanted _him_ dead, but hearing that more than one of his close friends wished for, essentially, his death sent him into a, kind of, depression.

The dragon slayer had always known that he was a demon, known that he was E.N.D., all because he had been reminded over and over and over, again; after all, while he was with Igneel, Zeref had visited one too many times. However, Natsu could never bring himself to say a word about it, to his friends.

 _What if they hate you?_

 _They won't._

 _How do you know? They hated all the other demons._

 _The other demons did bad things, hurt our family._

 _And you won't?_

 _Of course not._

"-atsu? Natsu?" Lucy's worried voice broke through his internal debate.

"What?" Natsu asked, startled.

The blonde gave him a concerned look. "You were spacing out."

"Oh." Natsu still felt sick and out of sorts and he, really, really, didn't want to talk, anymore.

Gray smirked in amusement. "Flame brain."

Natsu glared back, his anger, spontaneously, flaring up, but he didn't want to fight. He just grabbed what was left on his plate and headed for the exit.

"I'm leaving."

"Why? The sun hasn't even set." Gray asked, frowning.

"'Cause I feel like it." Natsu said, glowering at the ice mage, before he slammed the doors behind him.

Natsu stomped away, no real destination in mind, as he decimated what was left of his dinner. He didn't quite know how to handle his feelings on the situation and they ended up manifesting in that, earlier, bitterness.

 _He didn't deserve that._

 _He was being a jerk!_

 _Was he? Really?_

 _Of course! Him and his stupid, ugly face!_

 _You're sure you aren't just upset about the fact that he wants to kill you?_

 _He doesn't want to kill me!_

 _But he just said it._

 _He doesn't know I'm E.N.D.!_

 _He'd probably still kill you, if he knew. After all, you'd still be a dangerous demon._

 _I haven't done anything remotely dangerous!_

…

 _Okay! So I have done some destructive stuff, but we all do!_

 _You'll just do more damage, than everyone else._

"No. I. won't." Natsu growled, as he, viciously, kicked a rock, sending it flying.

He went silent and he heard the rock land with a plop, it had fallen into water. Natsu looked up at his surroundings, he hadn't realized that he had walked to the river. The slamander let out a deep sigh, feeling his anger slipping away and dejection taking its place. He shuffled to the edge of the river and slumped to the ground, hugging his knees, as he curled in on himself, watching the water.

* * *

Lucy rounded on him. "Gray! What did you do?!"

"I didn't do anything!" Gray retorted, indignantly.

"Oh really?" Gray whipped around, towards the voice, Erza was behind him. "He seemed pretty upset."

"I swear I didn't!" Gray insisted, irritated at their accusations. "He just got all grumpy for no reason. Besides, if he _was_ mad at me he would have just picked a fight."

Happy flew over to the group. "Hey I heard the door slam wh- Wait, where's Natsu?"

"He left." Gray muttered.

"What? Why?" Happy asked, a little hurt that his friend would leave without him.

"Gray set him off." Lucy explained.

"But, why'd he leave?" Happy asked, worried and confused.

"I don't know," Gray grumbled. "maybe he was tired."

Lucy huffed. "You know that's not true. He got mad after _you_ called him a flame brain!"

"That's hardly something for him to get sore over!" Gray countered, hotly.

"You still upset one of your friends." Erza said, more calmly.

Gray stood up, angrily. "We do that all the time!"

"I know, but he must have already been disgruntled, before you said something." Erza tried to explain.

"He _was_ spacing out." Lucy added.

Gray didn't know what their problem was. He hadn't done anything out of the norm and yet they weren't letting it go! This was all that idiot's fault!

Gray spoke, through gritted teeth. "If you guys really aren't gonna let it go, I'll go find out what's biting him."

Lucy and Happy looked thoroughly surprised, while Erza had a satisfied smile on her face. So, Gray, promptly, left, with no intent to do anything, but vent his irritation onto the dragon slayer.

.

.

.

Gray went to check Natsu's house, not there. He looked around the town for a bit, but ended up calling it quits, once it started getting dark. He was going to go back to the guild hall, but ended up walking along the river instead.

 _Seriously, where is that hot head?_

Now that his anger had begun to fade, Gray was actually a bit worried, although, he'd never admit that. Natsu never got that easily upset, he would usually just, playfully, throw a nickname back.

 _What happened to make him so heated?!_

That's when he spotted the pink-haired dragon slayer up ahead, on the bank. He was curled up into a ball, staring out at the river.

"Oi, Natsu!" Gray called out, as he was still a little ways away.

Natsu looked up in shock and quickly wiped his eyes, as Gray continued to walk towards him.

 _I must be seeing things. There's no way the flame brain would be crying over a stupid nickname._

When he got a bit closer, Gray asked, "Why are you out by the river?"

"Is that a problem?" Natsu snapped, but he instantly flinched. "Sorry."

Gray's eyes widened. They never apologized to each other over something _that_ stupid.

 _Something must be bothering him pretty bad..._

Gray sat down beside him. "So, why'd you storm off?"

"No reason." Natsu mumbled. "Why are you here, anyway?"

"'Cause _someone_ up and vanished after I called him a flame brain. Which resulted in me getting assaulted by some angry girls."

Natsu's mouth twitched upwards, in amusement.

"By the way," Gray continued, glad Natsu had smiled, a little. "I don't believe your sitting, huddled up by the river, for no reason."

Natsu murmured his reply. "...You won't, by any chance, let me sit in peace and quiet?"

Gray tilted his head back. "Maybe, but if I went back empty handed, I'd probably be murdered."

Natsu let out a deep sigh. He seemed unwilling to have this conversation.

"...and, besides," Gray continued. "when do you like peace and quiet?"

Natsu flushed, in indignation. "It can be nice!"

Gray gave a meaningful chuckle, remembering some of his own, good and bad, times by the river. "Yeah, it can be."

Silence wafted over the pair, for a while, as they watched the river, now under a sky filled to the brim with stars.

"Gray…?" Natsu asked, his voice spilling over with cautiousness and worry.

"Yeah?" Gray returned, turning to look at his friend, who seemed to have a deep fixation on the grass.

"You know that I would never...hurt you, right?" Natsu continued, anxiously, now pulling up the turf.

Gray looked at him funny, but he was concerned. "We fight all the time, squinty eyes."

Natsu looked at him seriously, before turning away, again. "I mean, I would never hurt you badly or...or worse."

Gray tried to reassure him. "Okay, I didn't think you would."

Natsu continued, quietly, now pulling up large quantities of grass, as he spoke. "I promise I wouldn't do it, no matter the reason."

Gray didn't know what to say. Natsu was so fidgety that he looked like he was waiting to hear the answer to a marriage proposal, but, for the love of everything, Gray could not figure out what the reason was, for this.

So, Gray opted to just mirror Natsu's words, even if it was kind of embarrassing to say out loud. "Just so we're clear, you know that I would never try to, actually, hurt you either, right?"

Gray must have said the right thing, because he felt so much of the tension vanish and Natsu's overall posture seemed to soften. Although this should have been relieving, it just concerned Gray even more.

* * *

Natsu had never been more happy to hear words in his life and a large portion of his stress dissipated.

 _Thank god!_

 _You do realize he could change his mind, once he knows what you are._

Natsu frowned at the thought.

 _I'm not going to let that happen._

 _Don't kid yourself! You know it'll come out eventually!_

"Natsu…" Gray said softly.

Natsu turned to face the ice mage, putting aside the internal conversation, that he hated so much.

"...are you scared that _I'm_ going to hurt you?" Gray continued, looking slightly wounded.

Natsu stiffened. Of course he was scared! He felt like an intruder, a liar. He knew that he was being hunted, but was hiding; he was like a wolf in sheep's clothing.

The fear was evident in Natsu's eyes, so Gray didn't wait for a response. " _Why_?"

Natsu turned away, in shame. The distress was clear in Gray's voice and Natsu hated the fact that he had put it there.

 _See? You've already hurt him._

Natsu didn't know how to respond. He couldn't very well _tell_ Gray why he was like this, so he ended up fumbling with his words.

"I- Well it's- it's- I don't know...it's a...feeling...that I...have."

Natsu glanced back at Gray, so many emotions were flickering in his eyes, but it was hurt that was written, all over his face.

 _Why don't you just come out and say?_

 _I want to stay with Fairy Tail…_

 _You'll only hurt them, like you're hurting Gray right now._

Gray let out a deep sigh. "I'll never hurt you, no matter what, okay?"

Natsu's head snapped towards Gray, guilt plastered on his face and the ice mage didn't fail to notice.

"I don't really know what brought this on," Gray continued, quietly. "but I've never once wished any, real, pain on you."

"...I'm sorry, Gray," Natsu murmured. "I'm being a real ass."

"Stop apologizing," Gray demanded. "It's weird, for you."

Natsu blinked in surprise.

Gray went on. "I can see that you feel bad about this, so I don't think it's your fault that you feel this way."

"Gray…" Natsu wasn't able to finish speaking.

"Natsu," Gray said sternly. "You're part of my family and Fairy Tail protects our family."

"I know that…" Natsu mumbled.

"No, you don't." Gray insisted. "Like I said before, no matter what this is about, I'll never hurt you, I promise."

 _I want to trust in you._

Natsu took a deep breath, hesitantly. "...I believe you, Gray."

Gray smiled in relief, seeing Natsu's eyes soften.

"So, are you ready to head back to the guild?" Gray asked.

"Why don't we just stay out here, for a bit?" Natsu replied.

Gray laid down. "Okay, flame brain."

Natsu followed suit. "...Thank you, ice block."

.

.

.

Natsu and Gray both regretted not keeping their promises, in the future.

* * *

 _ **Didn't exactly end it on a happy note, did I?**_


End file.
